RustyBadRobot

Rusty Social Image Share resizes your post thumbnail to perfectly fit to the Facebook Share dimensions whilst keeping your original image dimensions.
See the <a href="https://wordpress.org/extend/plugins/rusty-image-share/screenshots/" rel="ugc">screenshots tab</a> for more details.

Rusty Social Image Share

Keep your original Featured Image proportions whilst sharing to Facebook.

Makeworthy Media

Disables WordPress from generating image thumbnails when you upload a PDF. This behavior was introduced in WordPress 4.7, so this plugin isn’t needed for any version older than that. Not all web hosts support the ability to generate images from PDFs either, so even if you have 4.7 or newer you might not need this.

Disable PDF Thumbnails

Disables WordPress from generating image thumbnails when you upload a PDF.

Rusty Social Image Share vs Disable PDF Thumbnails